Dyeing polyamide fibers with a yellow monazo acid dye

ABSTRACT

DYEING POLYAMIDE FIBERS WITH A DYEBATH CONTAINING DISODIUM DODECYLIDIPHENYLETHER DISULFONATE AND THE YELLOW ACID DYE OF THE FOLLOWING STRUCTURE   1-(4-CL-PHENYL),3-CH3,4-((2-CL,5-(M-O3S-)PHENYL)-N=N-)-   PYRAZOLE   WHERE M IS H, AMMONIUM RADICAL OR ALKALI METAL.

United States Patent 01 lice 3,563,635 Patented Feb. 16, 1971 US. Cl.8-41 2 Claims ABSTRACT OF THE DISCLOSURE Dyeing polyamide fibers with adyebath containing disodium dodecyldiphenylether disulfonate and theyellow acid dye of the following structure I CH3 y 1| N SOJIVI H N whereM is H, ammonium radical or alkali metal BACKGROUND OF THE INVENTIONThis invention is directed to a process for dyeing polyamide fibers,particularly in nylon carpet.

Because of the wide acceptance and use of nylon, the dyeing of polyamidefibers in their various forms has become a very large and competitivebusiness. Several classes of dyes are used for dyeing polyamide fibers,each class having generally some advantages and some disadvantages.Disperse dyes were the first type to be recommended. They are believedto dye by dissolving in the polyamide fiber, without chemical reaction.They therefore give level dyeings on all types of polyamide fibers, thedyeings being unaffected by chemical differences. Disperse dyes have notmet all the needs of the carpet dyer. Very bright dyes and dyes ofmaximum light and fume fastness are not found among the disperse dyes.These qualities are more often found among the acid dyes. The reasonthat acid dyes, with these generally superior qualities, have not beenadapted for nylon carpet dyeing is the problem of lack of uniformity.

Acid dye molecules are assumed to associate With polyamide molecules atcationic ammonium end groups in the polymer chain. Thus, any lack ofuniformity in am monium end groups among the fibers used in making atextile product will be reflected in the lack of uniformity of dyeing inacid dyed material. In carpeting made from continuous filament polyamidefibers, such lack of uniformity is evidenced as a streaky dyeing. Thisis particularly noticeable in open width dyeing of polyamide carpetswhere 15 foot by 100 foot loops are dyed in large kettles, called becks.Unassisted acid dyes will expose lack of uniformity in the fibers aswell defined streaks, lighter or darker than the surrounding area.

A second major difficulty in dyeing large carpets in becks is theproblem of lack of levelness, or uniformity of the shade depth from sideto center to side. This problem exists with any type of dye, but isgreater with acid dyes or any site-dyeing dyes which associatechemically with the fiber molecules. The problem is minimized by carefuladdition of the dye to the bath and by efficient agitation, butpractical experience has shown that such expedients are not sufiicientto solve the problem.

Over the years a number of methods for overcoming the above-listeddifficulties have been tried. Three general methods will be mentioned:

The first of these is the use of swelling agents or high temperature toopen up the fiber. This concept suggests that if the dye could move morerapidly into and within the fiber, dye transfer would be facilitated,physical differences between yarns would be less significant, and dyeswhich perform poorly under normal conditions might produce more uniformdyeings.

A second method for obtaining improved level dyeing with acid dyesinvolves complexing the dye in the dyebath with a cationic materialbefore application of the dye to the fiber. The dye complex is formed ata low temperature and at a low pH, then, under the influence of thehigher dyeing temperature, the complex gradually dissociates and the dyeion becomes available to diffuse into the fiber. Since at any given timethe actual concentration of free dye ion is very low, level dyeing isobtained as it would be from a very dilute dyebath.

A third method for promoting levelness uses anionic dyeing assistants.The mode of operation is within the nylon fiber, not in the dyebath aswas the case with the cationic approach. This method depends on thecompetition of certain colorless anions in the dyebath with the dye forthe positively charged dyeing sites in the fiber. Thus it becomes moredifficult for the dye molecule to find a point of attachment during theinitial stages of dyeing. As dyeing progresses, the anionic dye competesmore successfully with the colorless anionic assistant for dye sites,resulting in improved levelness of dyeing.

The process of this invention provides level dyeing of polyamide fiberswith a monazo acid type dye without streakiness.

SUMMARY OF THE INVENTION The process of dyeing fibers which comprisescontacting the fibers with an aqueous dyebath which contains disodiumdodecyldiphenylether disulfonate and the dye of the following structurel N S 03M H O N/ where M is H, ammonium radical or alkali metal.

DESCRIPTION OF THE INVENTION The dyeing process of this invention may becarried out using 20 to parts of water per part of textile materialwithout effect on the process efficiency.

The. disodium dodecyldiphenylether disulfonate dye assistant may beprepared according to the disclosure of US. Pat. 2,081,876. The amountused may vary from 0.5 to 4.0 weight percent of the fibers, thepreferred amount is from 0.5% to 2%. Lesser amounts are insufficient toinsure satisfactory leveling and streak coverage. Amounts greater than4% may lead to poor exhaust from the dyebath and consequent economicloss. Excessive amounts have also caused a diminution of lightfastness.

The dyeing process may be carried out in any convenient manner. In thedyeing of carpets, the preferred manner is to use a beck or large kettlein which to 100 foot loops are dyed. This process is particularly suitedfor full width, in the range of from 12 ft. to 15 ft., carpet dyeings.

Dyeing may be carried out at any pH in the range of from 3 to 7, withthe preferred range being from a pH of 6 to 7. Higher pHs tend to causepoor exhaust. Acetic acid or tetrasodium pyrophosphate may be used toadjust the pH of the dyebath.

The optimum temperature for the dyeing process is at the range of from95 to 100 C. Lower temperatures extend the time required and also givepoor exhaust.

The acid dye of this process was developed for dyeing bulked continuousfilament polycarbonamide fibers. It has successfully solved theuniformity problem in an economic manner. This dye also gives goodlevelness on flatwoven and knit fabrics. This dye is unusual among aciddyesin having good transfer properties. The dyeing assistant, disodiumdodecyldiphenylether disulfonate helps promote their transfer and ismuch superior in this respect to other anionic leveling agents.

As shown under Example 1 below, the yellow acid dye of this inventioncan be prepared by diazotizing 3- amino4-chlorobenzene sulfonic acid;coupling to l-pchlorophenyl-3-methyl-5-pyrazolone; isolating byfiltration; and drying.

The process of this invention, while related to the anionic dyeingsystem, does not depend on retarding the striking rate of the dye byeither a cationic or anionic agent, but is based on the interdependenceof the special anionic material together with the selected dye which hasthe ability to transfer well. The transfer principle, or ready mobilityof the dye, is the direct means of obtaining levelness. The anionicagent used, disodium dodecyldiphenylether disulfonate, aids thistransfer in a unique way and, at the same time, competes with the dyefor the cationic sites within the fiber. When the dyeing problem isextremely difficult as in the open width dyeing of very wide nyloncarpeting, dye transfer can be further facilitated by the use of anonionic agent such as the condensation product of moles of ethyleneoxide with one mole of C alcohol along with the adjuvant of theinvention. As in older procedures, there is a competition for the dyesites. The novel feature of the present process is the ready movement ofthe dye and agent in and out of the fiber. This allows correction ofunlevelness by transfer, rather than requiring a controlled initialstrike.

The complete mechanism by which the adjuvant and the dye of thisinvention compete to provide improved level dyeing action onpolycarbonamide articles is not known in firm detail. The results,however, are clear. This dye is much less prone to develop a streakypattern in a fabric that is faulty in this respect. The exceptionaltransfer performance that takes place in the dyebath accounts for theimproved levelness of dyeing.

It is well known in the art that there are wide variations inlevel-dyeing properties among the many acid dyes available; but inaddition to this, other factors such as color fastness, draw rate,solubility, etc., must be considered. Above all, maximum lightfastnesswas a major criterion of acceptability. In its shade class, the dye ofthis invention was found, surprisingly, to offer technical advantagesever known dyes of somewhat similar structure, when used with therecommended adjuvant for dyeing polyamide fibers.

4 The following examples are representative of the process of thisinvention. All parts are by weight unless otherwise specified.

EXAMPLE 1 The yellow acid dye of this invention was prepared in thefollowing manner. A solution was prepared containing 11.5 grams of3-amino-4-chlorobenzene sulfonic acid sodium salt, 25 ml. of 37%hydrochloric acid and ml. of water. Ice was added to cool to 10 C. and10 ml. of 5 N sodium nitrite was added over 5 minutes. A small amount ofsulfamic acid was added to destroy the excess nitrite.

A coupler solution was prepared at 25 C. containing 125 gram ofl-p-chlorophenyl-3-methyl-5-pyraz0lone in ml. of water and 2.1 grams ofsodium hydroxide. To the coupler solution was added a solution of 12grams of anhydrous sodium carbonate in ml. of water, and the entiresolution cooled to 8 to 10 C.

The diazo solution was added to the coupler solution, maintaining thetemperature at 8 to 10 C. The solution was heated to 50 C. to completethe reaction. The slurry was stirred over night, then filtered. The wetproduct was dissolved in dilute caustic soda solution, filtered, and theproduct reprecipitated with hydrochloric acid,

' then filtered, washed and dried. The yield was 17.5 grams of dryproduct. The finished product was used in the following examples.

EXAMPLE 2 The following example illustrates the dyeing of nyloncarpeting using the yellow acid dye of Example 1. The carpeting is madeby tufting polycarbonamide yarn onto a jute or polypropylene backing.The continuous filament polycarbonamide yarn used for this is3700-denier, 204- continuous filaments, trilobal, jet-bulked yarn,melt-spun from poly (hexarnethylene adipamide) flake. The yarn isjet-bulked with the jet taught by Hallden et al. in US. Pat. 3,005,251.

Thirty parts of said carpeting are installed in dyebath equipment.First, the carpet is scoured at 82 C. for 20-30 minutes in a hath madeup of 1000 parts water, 0.2 part of a nonionic surfactant (thecondensation product of 20 moles of ethylene oxide with one mole of Calcohol), 0.6 part concentrated ammonium hydroxide and 0.15 part sodiumhydroxide. The bath is dropped and the carpet is rinsed with cleanwater. A dyebath is then made up of 1000 parts water, 0.3 part ofdodecyldiphenylether disulfonic acid, disodium salt according to thedisclosure of US. Pat. 2,081,876, 0.03 part of the yellow acid dye ofExample 1 and 0.6 part of monosodium phosphate. The pH is adjusted to6.0 by addition of acetic acid or disodium phosphate. The bathtemperature is raised to 99 C. over a 45-1ninute period and the dyeingis continued for one hour. The bath is dropped and the carpet is given awarm water rinse.

When the pH of the dyebath is adjusted to 6.5, instead of 6.0 as in thepresent example, similar results are obtained.

The dye of the present invention may be applied in this manner to giveshades having excellent levelness and lightfastness. Potentialstreakiness is effectively restrained. Wool and silk may also be dyed infast shades by the proress of this example.

EXAMPLE 3 A number of dyes of structure similar to the yellow acid dyeof Example 1 were synthesized and compared with regard to color transferand lightfastness.

The test for transfer is carried out by exposing a piece of undyedcarpeting and a piece of previously dyed carpeting in a bath containingall the regular materials as in Example 2 except the dye itself. Afterthe standard dyeing time, the samples are removed, dried and compared.With perfect transfer, 50% of the dye will be on each sample, and bothwill have the same shade. If none of the dye transferred from the dyedto the undyed sample, percent transfer would be 0. Gradings are made byvisual comparison. Dyes with satisfactory transfer properties will givelevel dyeings on full width carpets by piecedyeing when the process ofthis invention is used. Satisfactory streak coverage is also obtained,this quality depending on the efficiency of the adjuvant in maskingfibers containing higher or lower concentration of amine end groups.

The lightfastness test was performed according to the AmericanAssociation of Textile Chemists and Colorists procedure titled ColorPastness to Light, Tentative Test method 16 E-1964, using a Xenon Lampfor 80 hours. Lightfastness was evaluated according to the followingscale:

5-Negligible or no change 4-Slightly changed 3Noticeably changedZ--Considerably changed 1Much changed It will be noted from the resultswhich appear in Table I that relatively slight changes in the chemicalmake up of the dye cause profound changes in the dye properties.

TABLE I.YELLOW ACID TYPE DYES Percent The yellow acid dye of thisinvention was used to dye duplicate pieces of nylon carpet with andwithout the EXAMPLE 4 Much, to considerably weaker.

additive disodium dodecyldiphenylether disulfonate. Similar dyeings weremade with another representative A Comparison was made of the transferqualities of the 7 acid yellow dye at the same time. The resultspresented yellow acid dye of this invention and a representative yellowacid dye. The dyeings were carried out as in Example 2. It will be seenfrom the results presented in Table II that the yellow acid dye of thisinvention compares favorably with the other representative acid dye.

in Table III illustrate the eifect of the dyeing assistant disodiumdodecyldiphenylether disulfonate in promoting transfer and shows thepossible variations to be expected in the transfer properties of aciddyes, and that the dye of the present invention is superior in thisproperty.

TABLE IILEFFEC'1 O1" DYElNG ASSISTANT Percent; Dye Assistant transferYes 40 -N=N lcH, No 35 N SOzNfl HO N C. I. acid yellow 40 1350s o It isto be understood that the preceding examples are representative and thatsaid examples may be varied within the scope of the total specification,as understood by one skilled in the art, to produce essentially the sameresults.

As many widely difi'erent embodiments of this invention may be madewithout departing from the spirit and scope thereof, it is to beunderstood that this invention is not limited to the specificembodiments thereof.

I claim:

1. The process of dyeing polycarbonamide fibers which comprisescontacting said fibers with an aqueous dyebath containing disodiumdodecyldiphenylether disulfonate and the dye of the following structurei Ii SOiM

UNITED STATES PATENTS 20 1,962,226 6/1934 Woodward. 2,081,876 5/1937Prahl.

FOREIGN PATENTS 25 966,677 8/1964 Great Britain.

988,829 4/1965 Great Britain.

GEORGE F. LESMES, Primary Examiner B. BETTIS, Assistant Examiner US Cl.X.R. 8-179, 89

